The 43-year-old has moved to Loftus Road following a stint at Manchester City in a similar role in 2008.
"I am very pleased to be here," Rigg told the club's official website. "When I sat down with the owners and Mark recently they sold the project at Queens Park Rangers to me.
"I see where they want to take the club and it is something I want to be a part of. I have worked with Mark in a number of different roles so I have a very good understanding of what he wants and what he needs.
"Player acquisition is a big part of football and it is where an enormous amount of investment is made. That's where we must get it right. My role involves a mixture of looking at the immediate needs for the football club as well as trying to make sure we have a long-term plan in place for bringing players through into the first team."
Rigg also has experience working with the Welsh national team and Blackburn Rovers.